喝咖啡可以预防某些癌症

Coffee is one of the world's most widely-enjoyed beverages. Flavor aside, scientists have recognized it as a complex blend of chemical compounds with potential health effects, both good and bad. Now, new research suggests that if you drink enough coffee, it might help you avoid certain kinds of cancer.

Dr. Mia Hashibe  of the University of Utah School of Medicine was interested in the link between coffee drinking and certain cancers of the head and neck. Researchers have looked into this before, but without reaching any firm conclusions.

"There were a few studies, but the findings were not consistent across the studies," she said, "so this finding from our current study was quite a surprise. We didn't really have any expectation of which direction it could go into."

To sort out the confusion, Hashibe and her colleagues used statistical techniques to, in effect, make one big study out of the previous smaller studies.

So we combined data across nine individual studies, so we have a lot more power than previous studies that looked at this. And we included 4,000 cancer patients who have cancer of the oral cavity and pharynx [throat]. And then 9,000 controls, so controls are people who do not have cancer."

Those studies – in Europe and the United States – found that people who drank a lot of coffee were less likely to develop cancers of the mouth and throat.

"We saw a protective effect for drinking more than 4 cups of coffee per day," Hashibe said. "This was the 40 percent decrease in risk. We did not observe an association for drinking three cups or less per day."

In an interview via Skype, Mia Hashibe said there was a weak link between cancer risk and drinking decaffeinated coffee, but it wasn't statistically significant. And she and her colleagues found no evidence that drinking tea provided the same protection as drinking coffee. Their research is published in the journal Cancer Epidemiology, Biomarkers & Prevention.

Hashibe says it is not clear how coffee might protect drinkers from certain cancers.

"There are a few chemicals that are known to be antioxidants in coffee. So we are thinking perhaps those compounds are playing some sort of protective role against several cancers."

If those compounds can be isolated, maybe someday you'll be able to take an anti-cancer pill, but for us coffee lovers, the answer may just be another refill.